Manganese oxide (MnOx) is used as a material of a lithium manganese oxide used as a cathode material of a lithium secondary battery. In order to obtain a cathode material of a lithium secondary battery with a higher battery performance, a so-called metal-substituted lithium manganese oxide having a part of manganese substituted by another metal has been reported.
As a method for producing such a metal-substituted lithium manganese oxide, a method has been reported in which in addition to a lithium material and a manganese material, another metal compound is added, followed by mixing and firing (Patent Document 1) or a method has been reported in which the respective materials are finely ground and formed into a slurry, and the slurry is dried to obtain agglomerates, which are fired (Patent Document 2).
Further, a method has been reported in which from an aqueous solution in which calcium and magnesium are added at the time of synthesis of manganese oxide, manganese hydroxide containing them is obtained and oxidized to obtain manganese oxide containing calcium and manganese (Patent Document 3).
Further, as a cathode material of a lithium secondary battery with a higher battery performance, a combined lithium composite oxide has been reported.
To obtain a cathode material using a composite oxide, a method has been reported in which lithium hydroxide, γ-MnOOH, tricobalt tetraoxide and nickel hydroxide are mixed and fired (Patent Document 4).
Further, a solution containing manganese, nickel and cobalt is subjected to precipitation in the presence of a complexing agent to obtain cobalt manganese co-precipitated nickel hydroxide particles in which these elements are uniformly dispersed, which are used as a material of a cathode material (Patent Document 5).